Term 181
DCI
DCI connects two or more data centers over a network, enabling resource sharing, disaster recovery, and workload mobility.
Acronym study
Terms 181–210 of 1033 N10-009 acronyms and key terms. Each entry includes a plain-English definition and a link to the full 800-word glossary page with exam context and practice questions.
Term 181
DCI connects two or more data centers over a network, enabling resource sharing, disaster recovery, and workload mobility.
Term 182
A DDoS (Distributed Denial-of-Service) attack is a malicious attempt to disrupt normal traffic of a targeted server, service, or network by overwhelming it with a flood of internet traffic from multiple compromised systems.
Term 183
The Dead timer is the period an OSPF router waits to hear from a neighbor before declaring that neighbor as unreachable and removing it from the routing table.
Term 184
A deauthentication attack is a wireless network exploit where an attacker sends fake disconnection frames to force devices off a Wi-Fi network, often used to capture handshake data or disrupt connectivity.
Term 185
Decapsulation is the process in networking where a device removes headers and trailers from a data packet as it travels up the OSI model layers.
Term 186
A Dedicated Interconnect is a direct, private physical connection between your on-premises network and a cloud provider's network, bypassing the public internet for faster, more reliable, and more secure data transfer.
Term 187
A default app is the program that your operating system automatically uses to open a specific type of file or perform a certain task, such as opening a web link or viewing a photo.
Term 188
A default gateway is a network device, typically a router, that acts as the exit point for traffic from a local network to other networks, including the internet.
Term 189
A default route is a catch-all routing entry that tells a network device where to send packets when no specific route matches the destination address.
Term 190
The Default VLAN is VLAN 1 on most Cisco switches and it is the VLAN to which all switch ports belong by default until they are assigned to a different VLAN.
Term 191
The Demarcation point is the physical or logical boundary where the responsibility for a network or telecommunications line shifts from the service provider to the customer.
Term 192
Dependency scanning is the automated process of checking software components for known security vulnerabilities and outdated versions.
Term 193
In a Spanning Tree Protocol network, a Designated port is the port on a network segment that has the best path to the root bridge and is responsible for forwarding traffic toward the root bridge.
Term 194
A router elected in an OSPF multi-access network to manage link-state updates and reduce routing protocol traffic.
Term 195
DevSecOps is a software development practice that integrates security into every phase of the DevOps lifecycle, making security a shared responsibility from the start.
Term 196
Dynamic Host Configuration Protocol (DHCP) automatically assigns IP addresses and network settings to devices on a network, so they can communicate without manual configuration.
Term 197
A DHCP pool is a reserved set of IP addresses that a DHCP server can assign to devices on a network automatically when they request a connection.
Term 198
A network device or feature that forwards DHCP broadcast messages between clients and servers on different subnets so that IP address assignment works across multiple network segments without a separate DHCP server on each one.
Term 199
A DHCP server is a network device or service that automatically assigns IP addresses and other network configuration parameters to devices on a network, eliminating the need for manual configuration.
Term 200
DHCP snooping is a network security feature that filters untrusted DHCP messages to prevent rogue DHCP servers from giving out false IP addresses.
Term 201
DHCPv6 is a network protocol that automatically assigns IPv6 addresses and other configuration settings to devices on a network.
Term 202
A differential backup copies all data that has changed since the last full backup, growing in size with each new backup until the next full backup is performed.
Term 203
Diffie-Hellman is a cryptographic protocol that allows two parties to securely exchange a shared secret key over an untrusted network like the internet.
Term 204
A cryptographic technique used to verify the authenticity and integrity of a digital message or document, ensuring it came from the claimed sender and was not altered.
Term 205
Digital Subscriber Line (DSL) is a technology that uses ordinary copper telephone wires to provide high-speed internet access to homes and businesses.
Term 206
Digital transformation is the process of using digital technology to fundamentally change how a business operates and delivers value to customers.
Term 207
Digital Visual Interface is a video display interface used to connect a video source, like a computer, to a monitor or projector, transmitting uncompressed digital video signals for clear, high-quality images.
Term 208
The Dijkstra algorithm is a mathematical method used by OSPF to calculate the shortest path between a router and every other router in a network.
Term 209
Direct Attach Copper is a type of high-speed copper cable used to connect networking equipment over short distances without needing separate transceivers.
Term 210
AWS Direct Connect is a cloud service that lets you create a dedicated private network link from your on-premises data center to AWS, bypassing the public internet for more consistent and secure connectivity.